ES2904672T3 - Exoskeleton structure adapted for the shoulder - Google Patents

Abstract

Exoskeleton structure (1) comprising: - a back assembly (2) intended to be attached to a user's back, - an arm assembly (3) intended to be attached to an arm of the user, - a locking device shoulder joint (4) that connects the back assembly (2) to the arm assembly (3), the shoulder joint device (4) comprising a first joint piece (11), a first pivot (10) that joins the first connecting piece (11) to the back assembly (2) allowing a rotation of the first connecting piece (11) with respect to the back assembly (2) around a first axis of rotation (X1) parallel to an axis of internal/external rotation of the user's shoulder, a second connecting piece (13), a second pivot (12) that joins the first connecting piece (11) to the second connecting piece (13) allowing a rotation of the second connecting piece (13) with respect to the first connecting piece (11) around a second axis of rotation (X2) orthogonal to the first axis of rotation rotation (X1), a third pivot (14) that joins the second connecting piece (13) to the arm assembly (3) allowing a rotation of the arm assembly (3) with respect to the second connecting piece (13) around of a third axis of rotation (X3) orthogonal to the second axis of rotation (X2), in which the second pivot (12) is arranged so that the second axis of rotation (X2) forms a non-zero angle with an axis of abduction/adduction of the user's shoulder and a non-zero angle with an axis of flexion/extension of the user's shoulder when the user is standing with arms relaxed along the body.

Description

DESCRIPTION

Exoskeleton structure adapted for the shoulder

field of invention

The invention relates to an exoskeleton structure.

State of the art

Effort assistance exoskeletons are mechanical structures that duplicate the structure of the human skeleton and allow the physical capabilities of the human body to be improved.

There are different types of effort assistance exoskeletons that depend on the tasks that the user must fulfill. Each type of exoskeleton allows to limit or reduce the effort provided by the user in the fulfillment of certain tasks.

There are, for example, exoskeleton structures that allow a user to be assisted when carrying out tasks that cause movements of a shoulder, in particular for lifting and handling loads. However, these structures do not generally allow adaptation to all movements of the shoulder. For example, these structures may allow flexion and extension movement of the arm, but not allow abduction and adduction movement of the arm.

Now, the shoulder complex is a complex joint system that has six cumulative degrees of freedom (combining the movements of the scapula and the shoulder itself).

Other structures have also been proposed that make it possible to better reproduce the movements of the shoulder. However, these structures generally take up a lot of space, which makes it difficult for the user to move.

On the other hand, the integration of several actuators in these structures causes an increase in the mass and energy consumption of the structure.

Finally, it should be noted that in certain chains of shoulder movements, certain exoskeleton structures can pass through configurations called "singular points", which causes the structure to block. Locking of the exoskeleton structure is the loss of a degree of freedom that appears in configurations in which two of the axes of rotation of the structure are aligned with each other. These locking situations require at least the reversal of the sequence of movements that have caused the singularity to release the user from his movements, and can even damage the exoskeleton structure and create discomfort for the user.

Document FR 3046052 describes a shoulder module for an exoskeleton structure that comprises a series of connecting pieces joined together by a series of pivots that allow rotation of abduction/adduction, internal/external rotation and flexion movements. /extension of the user's shoulder.

Summary of the invention

An object of the invention is to propose an exoskeleton structure that provides greater freedom of movement for the shoulder while being compact at the same time.

This objective is achieved within the framework of the present invention thanks to an exoskeleton structure comprising:

- a back assembly intended to be fixed on the back of a user,

- an arm assembly intended to be fixed on a user's arm,

- a shoulder connection device that connects the back assembly with the arm assembly, the shoulder connection device comprising a first connection piece, a first pivot that joins the first connection piece to the back assembly allowing a rotation of the first connecting piece with respect to the back assembly around a first axis of rotation parallel to an internal/external rotation axis of the user's shoulder, a second connecting piece, a second pivot connecting the first connecting piece to the second connecting piece allowing a rotation of the second connecting piece with respect to the first connecting piece about a second axis of rotation orthogonal to the first axis of rotation, a third pivot that joins the second connecting piece to the arm assembly allowing a rotation of the arm assembly with respect to the second connecting piece about a third axis of rotation orthogonal to the second axis of rotation,

wherein the second pivot is arranged such that the second axis of rotation forms a non-zero angle with an abduction/adduction axis of the user's shoulder and a non-zero angle with a flexion/extension axis of the user's shoulder when the user stands with arms relaxed along the body.

In said structure, the second axis of rotation forms a non-zero angle with an abduction/adduction axis of the user's shoulder and with a flexion/extension axis of the user's shoulder at the same time. Therefore, it is possible to design a structure in which a single actuator simultaneously allows the user to be assisted when a shoulder abduction/adduction movement takes place and when a shoulder flexion/extension movement takes place, thus allowing to reduce the mass of the structure and its energy consumption.

In addition, with this configuration of the second axis of rotation, the user can, for example, successively carry out shoulder flexion movements, followed by scapula adduction, and then a shoulder extension movement without the connecting device passing through a singular point, which avoids creating blocking situations.

The proposed structure may also have the following characteristics:

- the third pivot is arranged so that the third axis of rotation is orthogonal to the first axis of rotation, when the user is standing, with the arms relaxed along the body,

- the structure comprises an actuator including a stator and a rotor mounted rotatable with respect to the stator, one of the stator and the rotor mounted fixed on the first connecting piece, and the other being between the stator and the rotor mounted fixed on the second connecting piece, the actuator being suitable for generating a torque to drive the second connecting piece in rotation with respect to the first connecting piece,

- the arm assembly comprises an arm part suitable for coming to rest against the user's arm to drive the user's arm in rotation with respect to the user's back, by means of the actuator,

- the arm assembly comprises a first arm part suitable for surrounding the user's arm to fix the first arm part to the user's arm, and a second arm part rotatably mounted with respect to the first arm part so as to allow a rotation of the user's arm with respect to the second arm part, being at the same time capable of bringing the first arm part to rest against the user's arm in order to drive the arm in rotation by means of the actuator,

- the arm assembly comprises a third connecting piece and a fourth pivot, the third connecting piece having a first end connected to the shoulder connecting device by means of the third pivot, and a second end connected to the arm piece by means of of the fourth pivot,

- the fourth pivot allows a rotation of the arm part with respect to the third connecting part about a fourth axis of rotation parallel to the third axis of rotation,

- the third connecting piece includes two pieces mounted sliding one with respect to the other by means of a slider, the sliding of the pieces one with respect to the other allowing a shortening or a lengthening of the third connecting piece when a change occurs rotation of the arm set with respect to the back set,

- the arm assembly comprises a forearm part suitable for surrounding the user's forearm to fix the arm assembly on the user's arm, while allowing a rotation of the user's arm inside the forearm part when it occurs an internal-external rotation movement of the shoulder,

- the arm assembly comprises a fifth pivot connecting the forearm part to the arm part and allowing the forearm part to rotate with respect to the arm part around a fifth axis of rotation when the arm rotates user elbow,

- the joining device comprises a four-bar mechanism that joins the back assembly to the first pivot, the four-bar mechanism comprising four bars, and four joints that join the bars together forming a deformable parallelogram,

- each joint of the four-bar mechanism has an axis of rotation, each axis of rotation extending parallel to a direction orthogonal to a frontal plane of the user,

the connecting device further comprises an elastic return member suitable for exerting a return force tending to oppose deformation of the parallelogram.

Presentation of the drawings

Other features and advantages will also emerge from the following description, which is purely illustrative and not limiting, and should be read with reference to the attached figures, among which:

- figure 1 schematically represents an exoskeleton structure according to a possible embodiment of the invention, in a configuration in which the user is standing, with the arms relaxed along the body,

- figure 2 schematically represents the exoskeleton structure, in a configuration in which the user is standing, with the arm extended forwards, after having executed a flexion movement of the shoulder,

- figure 3 schematically represents the exoskeleton structure, in a configuration in which the user is standing, with the arm extended to the side, after successively executing a shoulder flexion movement and then a shoulder abduction movement ,

- Figure 4 schematically represents the exoskeleton structure when a flexion movement of the user's elbow takes place,

- figure 5 schematically represents a variant of the exoskeleton structure of figures 1 to 4.

Detailed description of an embodiment

Figure 1 illustrates a frontal plane F, a sagittal plane S and a transverse plane T of the wearer. In a known manner, the sagittal plane S is defined as a plane parallel to the median plane separating the left half from the right half of the user's body. The frontal plane F or coronal plane is defined as a plane perpendicular to the median plane and separating the body into an anterior or ventral part and a posterior or dorsal part. The transverse plane T or transverse plane is defined as a plane perpendicular to the median plane and separating the body into an upper part (on the side of the head) and a lower part (on the side of the feet).

In figure 1, the user is standing, with the arms relaxed along the body. The user is equipped with an exoskeleton structure 1 that allows his shoulder movements to be assisted.

The exoskeleton structure 1 comprises a back assembly 2 which, in normal use, is attached to a user's back, an arm assembly 3 attached to an arm of the user, and a shoulder attachment device 4 connecting the arm assembly back 2 to arm set 3.

The back assembly 2 comprises, for example, a belt 5 that surrounds the lower part of the user's trunk and a back piece 6 fixed to the lumbar belt 5 and extending along the user's spinal column.

The arm assembly 3 comprises an arm part 7 suitable for resting against the user's arm and a forearm part 8 suitable for surrounding the user's forearm to fix the arm assembly 3 to the user's arm.

The shoulder joint device 4 comprises a four-bar mechanism 9, a first pivot 10, a first joint piece 11, a second pivot 12, a second joint piece 13, a third pivot 14 and a third joint piece 15. .

The four-bar mechanism 9 joins the back assembly 2 to the first pivot 10. The four-bar mechanism 9 comprises four bars 16 and four joints 17 that join the bars 16 together to form a deformable parallelogram. Each joint 17 of the four-bar mechanism 9 has an axis of rotation, each axis of rotation extending parallel to a direction orthogonal to the user's frontal plane F, in normal use.

The shoulder joint device 9 further comprises an elastic return member 28 suitable for applying a return force to the four-bar mechanism 9 that tends to oppose the deformation of the parallelogram caused by the weight of the shoulder joint device 4 and of the arm assembly 3. More precisely, the elastic return member 28 comprises a spring that extends between two articulations located at the level of two opposite angles of the parallelogram. In the example illustrated in Figure 1, the spring is a traction spring that joins one of the joints 28 located at a higher angle, the closest to the sagittal plane, to another of the joints 28 located at a lower angle, the closest to the sagittal plane. away from the sagittal plane. The force of return exerted by the traction spring thus tends to drag the arm assembly 3 upwards with respect to the back assembly 2, so as to compensate for the weight exerted by the shoulder joint device and by the arm assembly. The stiffness of the elastic return member 28 can be adjusted as a function of the weight to be compensated.

The first pivot 10 joins the first connecting piece to the four-bar mechanism 9. The first pivot 10 allows a rotation of the first connecting piece 11 with respect to the back assembly 2 around a first axis of rotation X1 parallel to an axis internal/external rotation of the user's shoulder.

The second pivot 12 connects the first connecting piece 11 to the second connecting piece 13. The second pivot 12 allows a rotation of the second connecting piece 13 with respect to the first connecting piece 11 about a second axis of rotation X2 orthogonal to the first axis of rotation X1.

The second pivot 12 is arranged such that the second axis of rotation X2 forms a non-zero angle with an abduction/adduction axis of the user's shoulder and a non-zero angle with a flexion/extension axis of the user's shoulder when the user stands with arms relaxed along the body as illustrated in figure 1.

The third pivot 14 joins the second connecting piece 13 to the third connecting piece 15. The third pivot 14 allows a rotation of the arm assembly 3 with respect to the second connecting piece 13 around a third axis of rotation X3 orthogonal to the second axis of rotation X2.

The third pivot 14 is arranged such that the third axis of rotation X3 is orthogonal to the first axis of rotation X1 and the second axis of rotation X2, when the user is standing with the arms relaxed along the body. In addition, the third axis of rotation X3 forms a non-zero angle with the user's shoulder abduction/adduction axis and a non-zero angle with the user's shoulder flexion/extension axis when the user is standing, with arms relaxed throughout the body.

Thanks to the first pivot 10, the second pivot 12 and the third pivot 14, the connection device 4 allows a rotation of the arm assembly 3 with respect to the back assembly 8 according to three degrees of freedom.

The exoskeleton structure 1 also comprises an actuator 18 including a stator 19 and a rotor 20 mounted to rotate with respect to the stator 19. The stator 19 is mounted, for example, fixedly on the first connecting piece 11, and the rotor 20 is mounted, for example, fixed on the second connecting piece 13. The actuator 18 is suitable for generating a torque to drive the second connecting piece 13 in rotation with respect to the first connecting piece 11. The actuator can comprise, for example, an electric motor of the type without brushes or a geared motor.

The actuator 18 can be activated to assist the user's arm when an abduction/adduction and/or flexion/extension movement of the user's shoulder takes place, that is, to provide an additional effort that is added to the effort produced by the user. to produce shoulder movement.

The arm assembly 3 also comprises a fourth pivot 21. The fourth pivot 21 connects the third connecting piece 15 to the arm piece 7. The fourth pivot 21 allows a rotation of the arm piece 7 with respect to the third connecting piece. joint 15 about a fourth axis of rotation X4 parallel to the third axis of rotation X3.

The third connecting piece 15 has a first end connected to the second connecting piece 13 by means of the third pivot 14, and a second end connected to the arm piece 7 by means of the fourth pivot 21.

On the other hand, the third connecting piece 15 comprises two pieces 22 and 23 mounted sliding one with respect to the other by means of a slider. The axial sliding of the parts 22 and 23 with respect to each other allows a shortening or lengthening of the third connecting piece 15 when a rotation of the arm assembly 3 with respect to the back assembly 2 takes place, which allows adapting a misalignment of the axes of rotation X1, X2 and X3 with the actual center of rotation of the user's shoulder.

On the other hand, part 23 is rotatably mounted with respect to part 22 about the axis of sliding of part 23 with respect to part 22.

Lastly, the forearm part 8 allows a rotation of the shoulder inside the forearm part 8 when an internal-external rotation movement of the shoulder takes place.

Figure 2 schematically represents the structure of the exoskeleton 1, when the user is standing, with the arm extended forwards, after having executed a flexing movement of the shoulder.

The flexion movement of the shoulder simultaneously causes a rotation of the second connecting piece 13 with respect to the first connecting piece 11 around the second axis of rotation X2 and a rotation of the third connecting piece 15 with respect to the second connecting piece 13 about the third axis of rotation X3.

The bending movement can be assisted by activating the actuator 18. When activated, the actuator 18 in effect generates a torque that tends to drive the second connecting piece 13 in rotation with respect to the first connecting piece 11, and therefore consequently, to put the arm piece 7 supported on the user's arm to assist the arm when the shoulder flexion movement takes place. The arm piece 7 comes to rest against the user's arm to actuate the user's arm in flexion or extension with respect to the user's scapula, by means of the actuator 18.

As illustrated in Figure 2, once the user's arm is extended horizontally forward, the first axis of rotation X1 is parallel to the third axis of rotation X3.

Figure 3 schematically represents the exoskeleton structure, when the user is standing, with the arm extended to the side, after successively executing a shoulder flexion movement and a shoulder abduction movement.

The abduction movement of the shoulder simultaneously causes a rotation of the second connecting piece 13 with respect to the first connecting piece 11 around the first axis of rotation X1 and a rotation of the third connecting piece 15 with respect to the second connecting piece 13 about the third axis of rotation X3.

The abduction movement can be assisted by activating the actuator 18. When activated, the actuator 18 in effect generates a torque that tends to drive the second connecting piece 13 in rotation with respect to the first connecting piece 11, and therefore consequently, to put the arm piece 7 supported on the user's arm to drive the arm in rotation. The arm piece 7 comes to rest against the user's arm to drive the user's arm in abduction or adduction with respect to the user's scapula, by means of the actuator 18.

The actuator 18 thus serves both to assist the user when a flexion/extension movement of the shoulder takes place and when an abduction/adduction movement of the shoulder takes place.

Also, as illustrated in Figure 3, once the user's arm is extended horizontally to the side, the first axis of rotation X1, the second axis of rotation X2, and the third axis of rotation X3 are not two-way aligned. in two. The connecting device 4 avoids passing through singular points that could cause the exoskeleton structure 1 to block. In addition, the efficiency of the actuator is preserved.

As illustrated in figure 4, the arm assembly 3 also comprises a fifth pivot 27 that connects the forearm part 8 to the arm part 7. The fifth pivot allows a rotation of the forearm part 8 with respect to the part of arm 7 about a fifth axis of rotation X5 when a rotation of the user's elbow takes place. More precisely, the fifth pivot 27 allows a rotation of the forearm part 8 with respect to the arm part 7 about a fifth axis of rotation X5 when a flexion or extension movement of the user's elbow takes place.

The exoskeleton structure may further comprise a second actuator 24 including a stator 25 and a rotor 26 mounted rotatably relative to the stator 25. The stator 25 is mounted for example fixedly on the arm piece 7 and the rotor 26 is mounted for example fixed on the forearm part 8. The actuator 24 is suitable for generating a torque to drive the forearm part 8 in rotation with respect to the arm part 7. The actuator 24 can comprise, for example, an electric motor of the brushless type or a gearmotor.

The actuator 24 can be activated to assist the user's arm when a flexion/extension movement of the user's elbow occurs, ie to provide an additional effort that becomes added to the effort produced by the user to produce the movement of the elbow.

Figure 5 illustrates a variant of the exoskeleton structure of Figures 1 to 4. The exoskeleton structure 1 illustrated in Figure 5 is identical to the exoskeleton structure illustrated in Figures 1 to 4, with the exception of the arm assembly 3.

In this variant, the arm assembly 3 comprises a first arm part 31 suitable for surrounding the user's arm to fix the arm assembly 3 to the user's arm, and a second arm part 32 rotatably mounted with respect to the first part of arm 32. More precisely, in the example illustrated in figure 5, the second arm part 32 surrounds the first arm part 31, allowing at the same time a rotation of the first arm part 31 (and therefore a rotation of the user's arm) with respect to the second arm piece 32.

The third pivot 14 connects the third connecting piece 15 to the arm piece 7 by means of the fourth pivot 21.

In the example illustrated in figure 5, the arm assembly 3 does not comprise any forearm part 8. However, the arm assembly could also include a forearm part 8 joined to the second arm part 32 by means of a fifth pivot 27, as illustrated in figures 1 to 4.

Claims (13)

1. Exoskeleton structure (1) comprising: - a back assembly (2) intended to be fixed on the back of a user, - an arm assembly (3) intended to be fixed to an arm of the user, - a shoulder attachment device (4) connecting the back assembly (2) to the arm assembly (3), the shoulder attachment device (4) comprising a first attachment piece (11), a first pivot ( 10) that joins the first connecting piece (11) to the back assembly (2) allowing a rotation of the first connecting piece (11) with respect to the back assembly (2) around a first axis of rotation (X1) parallel to an internal/external rotation axis of the user's shoulder, a second connecting piece (13), a second pivot (12) that connects the first connecting piece (11) to the second connecting piece (13) allowing a rotation of the second connecting piece (13) with respect to the first connecting piece (11) around a second axis of rotation (X2) orthogonal to the first axis of rotation (X1), a third pivot (14) connecting the second connecting piece (13) to the arm assembly (3) allowing a rotation of the arm assembly (3) with respect to the second connecting piece (13) around dor of a third axis of rotation (X3) orthogonal to the second axis of rotation (X2), in which the second pivot (12) is arranged such that the second axis of rotation (X2) forms a non-zero angle with an abduction/adduction axis of the user's shoulder and a non-zero angle with a flexion/extension axis of the user's shoulder when the user is standing with arms relaxed along the body. 2. Structure according to claim 1, in which the third pivot (14) is arranged so that the third axis of rotation (X3) is orthogonal to the first axis of rotation (X1), when the user is standing, with the arms relaxed along the body. Structure according to one of claims 1 and 2, comprising an actuator (18) including a stator (19) and a rotor (20) rotatably mounted with respect to the stator (19), one of the stator and the rotor fixedly mounted on the first connecting piece (11), and the other being between the stator and the rotor fixedly mounted on the second connecting piece (13), the actuator (18) being suitable for generating a torque to actuate in rotating the second connecting piece (13) with respect to the first connecting piece (11). Structure according to claim 3, in which the arm assembly (3) comprises an arm piece (7) suitable for coming to bear against the user's arm to drive the arm in rotation by means of the actuator (18). Structure according to claim 3, in which the arm assembly (3) comprises a first arm part (31) suitable for surrounding the user's arm to fix the first arm part (31) to the user's arm, and a second arm part (32) rotatably mounted with respect to the first arm part (31) in such a way as to allow a rotation of the user's arm with respect to the second arm part (32), while being able to put the first arm part (31) abutting against the user's arm to drive the arm in rotation by means of the actuator (18). Structure according to one of claims 4 and 5, in which the arm assembly (3) comprises a third connecting piece (15) and a fourth pivot (21), the third connecting piece (15) presenting a first end attached to the shoulder attachment device (4) via the third pivot (14), and a second end attached to the or one of the arm pieces (7, 32) via the fourth pivot (21). Structure according to claim 6, in which the fourth pivot (21) allows a rotation of the arm part(s) (7, 31, 32) with respect to the third connecting part (15) around a quarter axis of rotation (X4) parallel to the third axis of rotation (X3). 8. Structure according to one of claims 6 and 7, in which the third connecting piece (15) includes two pieces (22, 23) mounted to slide one with respect to the other by means of a slider, allowing the sliding of the parts (22, 23) with respect to each other a shortening or lengthening of the third connecting piece (15) when a rotation of the arm assembly (3) with respect to the back assembly (2) takes place. Structure according to one of claims 1 to 8, in which the arm assembly (3) comprises a forearm piece (8) suitable for surrounding the user's forearm to fix the arm assembly (3) to the user's arm , allowing at the same time a rotation of the user's arm inside the forearm piece (8) when an internal-external rotation movement of the shoulder takes place. Structure according to one of claims 4 to 8 in combination with claim 9, in which the assembly The arm piece (3) comprises a fifth pivot (27) that connects the forearm piece (8) to the arm piece ⁽ 7 ⁾ and allows the forearm piece (8) to rotate with respect to the arm piece ( 7) about a fifth axis of rotation (X5) when a rotation of the user's elbow takes place. Structure according to one of claims 1 to 10, in which the connecting device (4) comprises a mechanism with four bars (9) that connects the back assembly (2) to the first pivot (10), the mechanism comprising with four bars (9), four bars (16), and four joints (17) that join the bars (16) together forming a deformable parallelogram. Structure according to claim 11, in which each joint (17) of the four-bar mechanism (9) has an axis of rotation, each axis of rotation extending parallel to a direction orthogonal to a frontal plane of the user. Structure according to one of claims 11 and 12, in which the connecting device (4) further comprises an elastic return member (28) suitable for exerting a return force tending to oppose deformation of the parallelogram.